Cyclic amp receptor protein (CRP) is a global transcriptional factor in many prokaryotes, capable of governing nearly half of the total genes in Escherichia coli. Through the method of error-prone PCR or DNA shuffling, we can first obtain CRP mutant library and then get the expected cell phenotype with enhanced resistance. In this article, we reviewed the following desired phenotype: enhanced tolerance towards oxidative stress, improved osmotolerance, enhanced organic solvent (toluene) tolerance, improved acetate tolerance of E. coli fermentation and improved ethanol tolerance during bio-ethanol production. We then concluded that CRP can also be applied in other host cells to get desired phenotypes. Last, we predicted potential applications of mutant CRP transcriptional factor.
Cyclic AMP Receptor Protein ; biosynthesis ; DNA Shuffling ; Escherichia coli ; metabolism ; Fermentation ; Metabolic Engineering

OBJECTIVE: To observe the effect of chronic unpredicted sequence of mild stress on the expression of cAMP-dependent protein kinase A(PKA) and phosphorylated cAMP-responsive element binding protein (P-CREB) in hippocampus of rats and the antagonism of antidepressors (fluoxetine). METHODS: Thirty-six male Sprague Dawley rats were randomly and equally allocated to 3 groups: A normal control group, a model group, and a fluoxetine group. All rats except the control group were singly housed and exposed to an unpredicted sequence of mild stressors. The different distribution and expression of PKA and P-CREB in the hippocampus of rats in different groups were investigated with immunohistochemistry and Westernblot technique. RESULTS: The positive PKA and P-CREB cells in the hippocampus of normal controls were the pyramidal cells and the granule cells. The PKA and P-CREB protein expression levels in the hippocampus of model rats were significantly lower than those of the normal controls (P<0.05). The PKA and P-CREB protein expression levels in the hippocampus of the fluoxetine group were significantly higher than those of the model group (P<0.05). CONCLUSION Chronic unpredicted mild stress can affect the PKA and P-CREB expression in hippocampus of rats and fluoxetine has antagonism against it.
Animals ; Antidepressive Agents, Second-Generation ; antagonists & inhibitors ; Cyclic AMP Response Element-Binding Protein ; biosynthesis ; genetics ; Cyclic AMP-Dependent Protein Kinases ; biosynthesis ; genetics ; Depression ; etiology ; metabolism ; Fluoxetine ; antagonists & inhibitors ; Hippocampus ; metabolism ; Male ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Stress, Physiological ; metabolism

OBJECTIVETo compare the differences of expressions of adenylyl cyclase (AC) and phosphodiesterase (PDE) in ejaculated spermatozoa between healthy volunteers and the patients with asthenospermia.

METHODSEjaculated spermatozoa were collected from healthy volunteers and the patients with asthenospermia. Reverse transcription polymerase chain reaction (RT-PCR) was used to detect mRNA expression of AC and PDE subtypes in human spermatozoa. The concentrations of cAMP and cGMP in the samples were detected by enzyme-linked immunosorbent assay (ELISA).

RESULTSCompared with healthy volunteers, expression of sAC mRNA and concentration of cAMP were significantly decreased in the patients with asthenospermia (P < 0.01) , while the expression of PDE4C mRNA was significantly increased at the same time (P <0.01). There were no marked differences in the expression of ACIII mRNA and concentration of cGMP between the two groups.

CONCLUSIONThe sAC down-regulation and PDE4C up-regulation are possible reasons for asthenospermia.

Adenylyl Cyclases ; biosynthesis ; Asthenozoospermia ; metabolism ; Cyclic AMP ; metabolism ; Humans ; Male ; Phosphoric Diester Hydrolases ; biosynthesis ; Reverse Transcriptase Polymerase Chain Reaction ; Spermatozoa ; metabolism

The present work was to investigate the effects of vasonatrin peptide (VNP) on cardiomyocyte protein synthesis induced by moderate hypoxia. In cultured neonatal rat cardiomyocytes, MTT methods, total protein measurement and (3)H-leucine incorporation were used to calculate the cell number and measure the protein synthesis of cardiomyocytes. Furthermore, radioimmunoassay was undertaken to observe the effects of VNP on the intracellular levels of cAMP, cGMP and the concentration of endothelin (ET) in the culture medium. The results showed that both the cell number and protein synthesis decreased with severe hypoxia for 24 h. In contrast, under moderate hypoxia, cardiomyocyte hypertrophy developed; the protein synthesis as evidenced by total protein content and 3H-eucine incorporation increased significantly. VNP reduced cardiomyocyte protein synthesis induced by moderate hypoxia in a dose-dependent manner. Furthermore, VNP increased the intracellular level of cGMP and decreased the concentration of ET in the culture medium under moderate hypoxia, but had no effect on the level of cAMP. These results suggest that VNP inhibits moderate hypoxia-induced protein synthesis in cultured neonatal rat cardiac myocytes. This effect is mediated, at least in part, by an increase in intracellular cGMP, a reduction in synthesis, and/or a release in ET of cardiomyocytes.
Animals ; Animals, Newborn ; Atrial Natriuretic Factor ; pharmacology ; Cell Hypoxia ; Cells, Cultured ; Cyclic AMP ; metabolism ; Cyclic GMP ; metabolism ; Dose-Response Relationship, Drug ; Endothelins ; biosynthesis ; Myocytes, Cardiac ; metabolism ; Protein Biosynthesis ; Rats ; Rats, Sprague-Dawley

The present study was aimed at examining the regulation of aquaporin (AQP)-2 water channels in the kidney in two-kidney, one clip (2K1C) hypertension. Rats were made 2K1C hypertensive for 6 weeks, and their expression of AQP2 channel proteins was determined in the clipped and contralateral kidneys. To examine the upstream affecting AQP2 channels, adenylyl cyclase activity was also determined. Along with the hypertension, in the clipped kidney, the abundance of AQP2 proteins was significantly decreased in the cortex, outer and inner medulla, while their trafficking remained unaltered. Concomitantly with the reversal of the blood pressure at 24 hours following removal of the clip, the AQP2 abundance also returned to the control level. The arginine vasopressin-evoked generation of cAMP was decreased in the clipped kidney, which again was reversed to the control level following removal of the clip. In contrast, the expression of AQP2 channels as well as the activity of adenylyl cyclase remained unaltered in the contralateral kidney. These results indicate an altered regulation of AQP2 water channels in the clipped kidney in 2K1C hypertension.
Adenylate Cyclase/metabolism ; Animal ; Aquaporins/*analysis ; Blood Pressure ; Cyclic AMP/biosynthesis ; Hypertension, Renovascular/*metabolism ; Kidney/*chemistry ; Male ; Rats ; Rats, Sprague-Dawley

ARNTL Transcription Factors ; deficiency ; metabolism ; Animals ; Cyclic AMP ; metabolism ; Gluconeogenesis ; Glucose ; biosynthesis ; HEK293 Cells ; Histone Deacetylases ; metabolism ; Humans ; Liver ; metabolism ; Mice ; Mice, Knockout

OBJECTIVETo observe the expression and effect of human calcitonin gene-related peptide (hCGRP) gene mediated by recombinant adeno-associated virus (rAAV) in primary cultured corporal cavernosum smooth muscle cells of the rat and explore the possibility of using CGRP gene for gene therapy in erectile dysfunction.

METHODSThe primary cultured corporal cavernosum smooth muscle cells of the rat were randomly divided into 4 groups and infected with recombinant virus VssHGCMV-hCGRP, VssHGCMV, VssC-MV-GFP and the untreated, respectively. CGRP-like immunoreactivity was measured by protein dot blot assay in the 24 h-culture medium, and intracellular cAMP and cGMP levels in the cultured cells were also determined using radioimmunoassay to ascertain bioactivity of transduced CGRP.

RESULTSThe exogenous gene was transferred into primary corporal cavernosum smooth muscle cells by VssHGCMV-hCGRP infection and efficiently expressed. Compared with the control group, intracellular cAMP level in the cell infected by VssHGCMV-hCGRP was significantly increased (48.7 +/- 1.1 nmol/L vs 7.8 +/- 1.4 nmol/L, P < 0.01), whereas cGMP level remained unchanged in two groups, and CGRP-like immunoreactivity was also detected in the culture medium infected by VssHGCMV- hCGRP.

CONCLUSIONThe system of secretory expressing bioactive peptide rAAV mediated gene transfer may be used to express efficiently exogenous gene in corporal cavernosum smooth muscle cells and affect cAMP level in the corporal cavernosum smooth muscle cells of the rat.

Animals ; Calcitonin Gene-Related Peptide ; biosynthesis ; genetics ; Cells, Cultured ; Cyclic AMP ; metabolism ; Cyclic GMP ; metabolism ; Dependovirus ; genetics ; Male ; Muscle, Smooth ; cytology ; metabolism ; Penis ; metabolism ; Rats ; Rats, Sprague-Dawley ; Recombination, Genetic ; Transfection

BACKGROUNDThere is currently considerable interest in the potential value of selective inhibitors of cyclic nucleotide phosphodiesterase 4 in the treatment of asthma. However, whether they influence eosinophilic airway inflammation-associated cough remains unclear. The objective of this study was to investigate the effects of selective phosphodiesterase 4 inhibitor SB207499 on cough response and airway inflammation in guinea pigs sensitized and challenged with ovalbumin.

METHODSForty sensitized guinea pigs were randomly divided into four groups: control (n = 10), challenge (n = 10), SB207499 (n = 10) and aminophylline (n = 10), then challenged with aerosol of 1% ovalbumin or saline. Two hours later, animals were intraperitoneally injected with either saline, 25 mg/kg of SB207499 or aminophylline. At the 24th hour, the injection was repeated with 2.5 mg/kg and 25 mg/kg SB207499 or aminophylline, then cough response to inhaled capsaicin and airway responsiveness to methacholine inducing a 150% of the peak airway pressure to the baseline (PC150) was measured. Finally, total cell number and differentials in bronchoalveolar lavage fluid were analysed.

RESULTSThe cough frequency per 3 minutes and PC150 in the challenge group were (22 +/- 4) times/3 minutes and (198 +/- 54) microg/ml, which were significantly different from (6 +/- 2) times/3 minutes and (691 +/- 81) microg/ml in the control group (P < 0.05, respectively). The injection of 25 mg/kg SB207499 significantly inhibited the increased cough response and airway hyperresponsiveness, the cough frequency and PC150 in guinea pigs were (13 +/- 2) times/3 minutes and (680 +/- 81) microg/ml (P < 0.05), which differed significantly from (18 +/- 2) times/3 minutes and (400 +/- 86) microg/ml after the administration of the same dose of aminophylline (P < 0.05). The inhibition of SB207499 on cough response was dose-dependent. Similarly, SB207499 decreased the total cell number and percentage of eosinophils in bronchoalveolar lavage fluid to (2.1 +/- 0.5) x 10(6)/ml and (20 +/- 5)% respectively, which were significantly different from (3.2 +/- 0.5) x 10(6)/ml and (29 +/- 5)% in the aminophylline group (P < 0.05, respectively) or (4.2 +/- 0.7) x 10(6)/ml and (35 +/- 4)% in the challenge group (P < 0.05, respectively).

CONCLUSIONPhosphodiesterase 4 inhibitor may be more useful than aminophylline for cough associated with eosinophilic airway inflammation via inhibiting airway inflammation and airway hyperresponsiveness.

3',5'-Cyclic-AMP Phosphodiesterases ; antagonists & inhibitors ; Animals ; Bronchial Hyperreactivity ; drug therapy ; Bronchoalveolar Lavage Fluid ; cytology ; Cough ; drug therapy ; Cyclic AMP ; biosynthesis ; Cyclic Nucleotide Phosphodiesterases, Type 4 ; Cyclohexanecarboxylic Acids ; therapeutic use ; Dose-Response Relationship, Drug ; Guinea Pigs ; Male ; Nitriles ; Ovalbumin ; immunology ; Phosphodiesterase Inhibitors ; therapeutic use

OBJECTIVETo explore the relationship between the overexpression of PKA RIalpha mRNA and cliniopathological parameters in lung cancer.

METHODSRT-PCR was used to detect the expression of PKA RIalpha mRNA in 54 cases with human lung cancer and matched normal tissues.

RESULTS(1) The expression of PKA RIalpha mRNA was significantly higher in cancer tissue (66.7%) than in normal tissues (20.4%) (P < 0.01). (2) The expression was significantly correlated with TNM stage (P < 0.01), being increased with TNM stage. (3) The expression was significantly higher in patients with positive lymph nodes than in those with negative lymph nodes (P < 0.01). (4) There were no significant associations of PKA RIalpha mRNA expression with histological type, differentiation grade or size of the tumor.

CONCLUSIONThis study indicates that the overexpression of PKA RIalpha mRNA may play an important role in the progression, metastasis and prognosis of lung cancer.

Adenocarcinoma ; metabolism ; secondary ; Adult ; Aged ; Carcinoma, Squamous Cell ; metabolism ; secondary ; Cyclic AMP-Dependent Protein Kinase RIalpha Subunit ; Cyclic AMP-Dependent Protein Kinases ; biosynthesis ; genetics ; Female ; Gene Expression Regulation, Neoplastic ; Humans ; Lung Neoplasms ; metabolism ; pathology ; Lymphatic Metastasis ; Male ; Middle Aged ; Neoplasm Staging ; Prognosis ; RNA, Messenger ; biosynthesis ; genetics

To investigate the function of testis sperm binding protein (TSBP) in sperm capacitation and acrosome reaction, the effect of the recombinant TSBP on the activity of protein kinase A was detected in the transfected cell line. With the use of prokaryotic expressing plasmid pGEX-5X-1/tsbp as template, the novel gene tsbp was amplified by PCR and a eukaryotic expressing vector pcDNA3.1/myc-His(-)B/tsbp was constructed. DNA sequencing and restriction endonuclease digestion analysis indicated that the eukaryotic expression vector pcDNA3.1/myc-His(-)B/tsbp had been constructed successfully. After the recombinant plamid being transfected into HEK293 cells, Western blot verified the expression of tsbp. Fusion protein His6-TSBP was purified from the cell lysate by immobilized metal-ion affinity chromatography (IMAC). Radioautograph revealed a higher PKA activity in the transfected HEK293 cells than in the control group, which indicates that TSBP can increase the activity of PKA.
Acrosome Reaction ; drug effects ; Cell Line ; Cyclic AMP-Dependent Protein Kinases ; drug effects ; Humans ; Male ; Recombinant Proteins ; biosynthesis ; genetics ; pharmacology ; Seminal Plasma Proteins ; biosynthesis ; genetics ; pharmacology ; Sperm Capacitation ; drug effects